The uncertainty principle (UP) of quantum theory is associated with the fundamental
nature of light, a quantized wave. When we also take account of the geometric nature
of gravity the UP becomes modified to the generalized uncertainty principle (GUP).
An amusing consequence of the GUP is that the Planck length is a minimum physically
meaningful distance.
The GUP also modifies the thermodynamic properties of a black hole, the Hawking
temperature and Bekenstein entropy. The modified temperature indicates that a small
radiating black hole should not radiate entirely away, but should leave behind a remnant
of about Planck mass. Such remnants are a possible dark horse candidate for the
dark matter.